Other mistake: Two Borg are discovered North of the Arctic Circle. One is covered in ice, the other encased in ice. Carbon dating shows the wreckage to be over 100 years old (to tie it in with Star Trek:First Contact). The Borg are inactive and unable to repair themselves until they are "defrosted". The temperature above the Arctic Circle doesn't usually drop below -100°F. The Borg have been shown to work very well in the vacuum of space which is 3-4K (roughly -454°F). If they can survive that, even being frozen in a solid block of ice would not slow them down. The nanites have to be in their "blood" and operate at the cellular level. That cannot be damaged by re-entry and the crash. [This is one of those entries that keeps being corrected and recorrected - I'll leave it up to people to make up their own minds.]
Other mistake: They show the tether and tether anchor fall out of the ship and fall behind, much in the same way as throwing something out of a car. However, it was still in the warp bubble and should have continued to be moving at warp 5 with the ships. We see later Columbia extend its warp bubble around Enterprise and Enterprise remains at warp 5 after cutting their engines. But, if the tether is no longer affected by the warp bubble, it should have been instantaneously out of view.